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Monday, June 30, 2008

CDI + Circuit Breaker / Rev-limiter / Cut-off Switch

CDI is known to give spark to the running engine, whether it is 2-stroke or 4-stroke. Inside a standard CDI circuit, there is a circuit breaker or rev-limiter or cut-off switch which limit the revolution of the engine. How does it work? Read on the article taken from Wikipedia. This article is about electrical circuit breaker but it can be used to relate to rev-limiter or cut-off switch in engines. In fact, we can't get away from electrical system when we are discussing about engines.

A device to open or close an electric power circuit either during normal power system operation or during abnormal conditions. A circuit breaker serves in the course of normal system operation to energize or deenergize loads. During abnormal conditions, when excessive current develops, a circuit breaker opens to protect equipment and surroundings from possible damage due to excess current. These abnormal currents are usually the result of short circuits created by lightning, accidents, deterioration of equipment, or sustained overloads.

Formerly, all circuit breakers were electromechanical devices. In these breakers a mechanism operates one or more pairs of contacts to make or break the circuit. The mechanism is powered either electromagnetically, pneumatically, or hydraulically. The contacts are located in a part termed the interrupter. When the contacts are parted, opening the metallic conductive circuit, an electric arc is created between the contacts. This arc is a high-temperature ionized gas with an electrical conductivity comparable to graphite. Thus the current continues to flow through the arc. The function of the interrupter is to extinguish the arc, completing circuit-breaking action.

In oil circuit breakers, the arc is drawn in oil. The intense heat of the arc decomposes the oil, generating high pressure that produces a fluid flow through the arc to carry energy away. At transmission voltages below 345 kV, oil breakers used to be popular. They are increasingly losing ground to gas-blast circuit breakers such as air-blast breakers and SF6 circuit breakers.

In air-blast circuit breakers, air is compressed to high pressures. When the contacts part, a blast valve is opened to discharge the high-pressure air to ambient, thus creating a very-high-velocity flow near the arc to dissipate the energy. In SF6 circuit breakers, the same principle is employed, with SF6 as the medium instead of air. In the “puffer” SF6 breaker, the motion of the contacts compresses the gas and forces it to flow through an orifice into the neighborhood of the arc. Both types of SF6 breakers have been developed for ehv (extra high voltage) transmission systems.

Two other types of circuit breakers have been developed. The vacuum breaker, another electromechanical device, uses the rapid dielectric recovery and high dielectric strength of vacuum. A pair of contacts is hermetically sealed in a vacuum envelope. Actuating motion is transmitted through bellows to the movable contact. When the contacts are parted, an arc is produced and supported by metallic vapor boiled from the electrodes. Vapor particles expand into the vacuum and condense on solid surfaces. At a natural current zero the vapor particles disappear, and the arc is extinguished. Vacuum breakers of up to 242 kV have been built.

The other type of breaker uses a thyristor, a semiconductor device which in the off state prevents current from flowing but which can be turned on with a small electric current through a third electrode, the gate. At the natural current zero, conduction ceases, as it does in arc interrupters. This type of breaker does not require a mechanism. Semiconductor breakers have been built to carry continuous currents up to 10,000 A.

Tuesday, June 17, 2008

Bermuda's Yamaha Sniper (LC135) Close Up

The sport rim here is branded Daiichi Alloy made from Thailand. It is very nice and eye-catching.

The exhaust pipe here is TENCUT Racing Pipe made from Philippine. For me, I prefer the exhaust from YY Pang and AHM since it is already tested and used in Malaysian Cub Prix Championship. But I don't know if the TENCUT pipe is used in racing in Philippine.

Friday, June 13, 2008

Yamaha Sniper (LC135) from Bermuda

Yamaha LC135 or Sniper in Bermuda

Yamaha LC135 is also known as Sniper in certain country such as Bermuda. The bike is not much different with what we have here in Malaysia. The rear brake is drum. The front brake is still one piston caliper even though the bike is equipped with manual clutch [in Malaysia the front brake is two-piston caliper for manual clutch version]. One thing that amazes me is the rims. I wonder what brand and model of rim it is. The exhaust has been already modified to a new one.

Different sticker design for Yamaha LC135

The other differences that we can spot is the design of the sticker, where it is written Sniper on the side fender. This bike belongs to Stephen in Bermuda.

Thanks Stephen for the picture!

Thursday, June 12, 2008

Yamaha LC135 Modification with X1R Coverset

LC135 is known as X1R in Thailand. The differences can be spotted from the missing of front head lamp replaced by a bigger lamp on the fairing.

The footrest used for this bike is different that the one which is used on the Yamaha LC135 50th Anniversary coverset whereby this one Racing Boy branded.

The radical dash here reminds me of Honda Nova Tena which is popular in Thailand and Kelantan in 1999. The dash here look a little bit naked due to the handle bar is not covered by the head lamp cover.

X1R sticker on the side fender shows that this bike is modded to resemble the bike from Thailand.

AHM or Ah Hong Motor exhaust is used again on this bike due to performance that can be gained from it and also because of the menacing looks that it provides to the bike. The price for the exhaust is also affordable since it is hollow inside to make the waste air from exhaust stroke to be extracted freely and quickly.

That's all for this one, but there are bonus picture below. Next, I'll try to bring you Yamaha LC135 MotoGP 2007 Coverset modification. But before that, there is an LC135 from Bermuda to be featured in this blog.

LC135 solid rear sprocket

Hard spring for firmer ride

Gear lever modification

Left side footrest

Tuesday, June 10, 2008

Malaysian Cub Prix 2008 Bike: Lagenda, Wave, Kriss, Shogun

The above article is taken from

In 2008, there are four dominant bike that is used for Malaysian Cub Prix racing.
The bikes involved in the racing are:

Yamaha Lagenda 110Z
Honda Wave 125S
Kriss 120 Sports
Suzuki Shogun 125

For more info and worthwhile reading,
hit the links for Malaysian Cub Prix Bikes

Sunday, June 8, 2008

Yamaha LC 135 50 Years Anniversary Coverset

Yamaha LC 135 50 Years Anniversary Coverset Side View. Original footrest has been removed and replaced with Yamaha racing footrest.

Front disc brake has been upgraded to bigger disc. Fork also has been replaced with LC 135 Trust inverted telescopic fork (fork terbalik / upside down fork). The caliper used is still one-piston kit from the original stock. The rim used is the same rim design used in Kawasaki ZX-6R also known as 'rim tulang ikan' (fish bone rim).

Close up view of the LC 135 inverted telescopic fork with TRUST logo. Look carefully!

Gazi gas monoshock rear suspension has been choosen since it can make the ride more firmer and dampen the suspension a little further than the original.

More Gazi gas monoshock suspension view.

The fairing has been customised with a little bit of eyelid.

Carbon fibre style front mudguard.

Yamaha logo on brake lever. Very nice and stylish.

Seat has been cut to get a lower riding position.

Notice the footrest which is branded YAMAHA not Racing Boy as most people would use.

More views of the YAMAHA branded footrest.

Also notice this brake is NISSIN branded, not Racing Boy. This brake is taken from the X1R version of LC 135 where the rear disc brake is standard in Thailand.

More view for the rear disc brake.

The exhaust used for this bike is AHM. There are several brand of racing exhaust that can be fitted to LC 135 being the Arrow and the most popular YY Pang. I have asked for the price for the AHM, and the shop told me it is cheap compared to the original LC 135 Catalyzer exhaust that cost about RM480. So, will you change your exhaust?

Exhaust bracket YAMAHA.

Overall view of AHM exhaust, YAMAHA racing footrest and NISSIN rear disc brake installation. Copy This!

Next I will bring to you YAMAHA X1R Coverset! Keep coming!


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